Scoped CakePHP Models

example.php

<?php
class Person extends AppModel
{
  // must explicitly set the useTable so child classes
  // use this not the CakePHP conventions based on their
  // class name
  public $useTable = 'people';
  // table people exists in the database with schema
  // id int(11) PK
  // type varchar(20) default 'contact' not null
  // full_name varchar(255) 
  // known_as varchar(50)
  // --- snip ---
}

// -------------

App::uses('Person', 'Model');
class Contact extends Person
{
  public function beforeFind($query)
  {
    parent::beforeFind($query);
    $query['conditions']['Contact.type'] = 'contact';
    return $query;
  }
}

// ------------------------

App::uses('Person', 'Model');
class Agent extends Person
{
  public function beforeFind($query)
  {
    parent::beforeFind($query);
    $query['conditions']['Agent.type'] = 'agent';
    return $query;
  }
}